I have a desktop dual booting XP/Ubuntu. I rarely use Ubuntu on this rig b/c it's primarily for gaming.
I have an older laptop with Ubuntu (no bells/whistles) for various things related to networking and web development.
My wife has a decent laptop with Ubuntu with all the bells/whistles. She uses it because she's a bit prone to getting viruses/spyware and all she does is email, surf the web, IM, and use her various google apps.

